Seasonal Action Guide

What to Do in the Garden in March (Cool-Climate US)

The short answer

In cool-climate gardens the season starts indoors in March, not outside. The headline jobs are starting summer vegetable seeds (tomatoes, peppers) indoors, University of Minnesota Extension's Upper Midwest calendar puts this window at mid-March through early May, finishing dormant pruning on trees and shrubs before new growth, cutting back last year's perennials, and direct-seeding spring cover crops like peas and oats as soon as the ground thaws.

Outdoor soil in zones 3-6 is usually still frozen or too wet for planting most of the month, so resist warm-climate calendars that say to plant now; the outdoor work is cleanup and pruning, and the planting is under lights.

Start and sow

Start summer vegetable seeds indoors; the Upper Midwest window runs mid-March through early May (UMN Extension).
In northern areas, Purdue advises waiting until the end of March or early April to start warm-season vegetables and flowers indoors so they don't outgrow their pots.
Direct-seed spring cover crops such as peas, oats, and clover as soon as the ground thaws (UMN Extension).
Keep seedlings under lights 12-16 hours a day and pot them up as they outgrow cell packs.

Prune and maintain

Finish pruning trees and shrubs while plants are still dormant, except early-spring bloomers, which wait until after flowering.
Cut back perennials in March and April (UMN Extension Upper Midwest calendar).
Remove old foliage from ornamental grasses before new growth starts.
Check stored bulbs and produce for decay; discard damaged items.
Begin fertilizing houseplants as new growth appears.

Get beds and plants ready

Plant bare-root trees and shrubs before they leaf out, as soon as soil dries enough to work (Purdue Extension).
Remove winter mulch from strawberry beds as new growth begins, but keep the mulch nearby in case of late freezes.
Remove weak, damaged canes from raspberries before new growth begins.
Follow last fall's soil-test recommendations when amending beds.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

University of Minnesota Extension — Upper Midwest home garden care schedule — Start summer vegetable seeds indoors mid-March through early May; cut back perennials March-April; direct seed spring cover crops (peas, oats, clover) as soon as the ground thaws
Purdue University Extension — March garden calendar (Indiana Yard and Garden) — Dormant pruning before new growth (except spring bloomers), bare-root planting before leaf-out, strawberry mulch removal at new growth, northern areas wait until late March/early April to start warm-season seeds indoors

Keep going

Garden Tasks for January (Warm-Climate US)

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Garden Tasks for February (Warm-Climate US)

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Garden Tasks for March (Warm-Climate US)

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Garden Tasks for February (Cool-Climate US)

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Garden Tasks for May (Cool-Climate US)

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Garden Tasks for September (Cool-Climate US)

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Garden Tasks for April (Cool-Climate US)

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Garden Tasks for August (Cool-Climate US)

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